Vent safety switch for heating systems



United States Patent 11113,542,018

[72] Inventors Kenneth C. Quick [56] References Cited 826 Walnut UNITED STATES PATENTS f f' gg' 836 Elm 2,1 12,554 3/1938 Beam 431/20 1 N 3 5? 2,184,983 12/1939 Tornquist.... 431/20 [211 P I4 1968 2,884,048 4/1959 Marble etal.... 126/110 fgf 233 3,403,962 /1968 Suffron m1. 431/ I Primary ExaminerCharles .l. Myhre Attorney-Zarley, McKee and Thomte ABSTRACT: A vent safety switch for gas-fired heating systems adapted to interrupt the gas supply to the gas burner VENT SAFETY FOR HEATING SYSTEMS when the temperature in the air vent chamber rises to a zclaimsfim'awmg predetermined level. The switch is placed in the air vent [52] U.S. Cl 126/116, chamber which is in communication with the heating system 431/20 chimney. The switch is electrically connected to the gas valve [51] lnt.Cl F24h 3/06, an is adapted to close the gas valve when the temperature {:24}, 9/20 rises to the said predetermined level. The switch has a manual Field ofSearch 126/110, reset pr i r n whi h m be m n lly Operated to 1 16; 431/20 cause the switch to be closed thereby opening the gas valve.

Patented Nov. 24, 170

llliii 54 W, WCM flrram/tys VENT SAFETYSWTTCH FOR HEATING SYSTEMS A blocked flue is obviously extremely hazardous in gas-fired heating systems. The continued operation of the heating system with a blocked flue can result in carbon monoxide spreading throughout the building. Conventional gas-fired, forced air heating systems utilize a limit control switch means which will shut off the gas supply valve when the temperature inthe heat exchanger becomes too high as a result of the blower fan failing to operate. However, the limit control switch means will again open the gas valve when the furnace cools off thereby again creating the safety hazard. Some gasfired heating systems are also provided with a pilot safety which closes the gas valve if the pilot light goes out. Neither the limit control switch means or the pilot safety will safely react to a blocked flue or an extreme downdraft condition to positively close the gas valve until the hazardous condition has been remedied.

Therefore, it is a principal object of this invention to provide a vent safety switch for gas-fired heating systems.

A further object of this invention is to provide a vent safety switch for gas-fired heating systems which closes the gas supply valve when the temperature in the vent reaches a predetermined level.

A further object of this invention switch for gas-fired heating systems having a means associated therewith.

A further object of this invention is to provide a vent safety switch for gas-fired heating systems which positively closes the gas valve until a manual reset has been operated. A further object of this invention is to provide a is to provide a vent safety manual reset vent safety switch for gas-fired heating systems which reacts to blocked fines and extreme downdraft conditions.

A further object of this invention is to provide a vent safety switch for gas-fired heating systems which is efficient, easy to install, safe and trouble-free.

These and other objects will be apparent to those skilled in the art.

This invention consists in the construction, arrangements, and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. 1 is a partial perspective view of a gas-fired heating system with portions thereof cut away to more fully illustrate the invention;

' HO. 2 is a fragmentary sectional view 2-2ofFlG.1-,

FIG. 3 is a partial elevational view of the heat exchanger portion of the heating system FlG.'4 is a perspective view FlG. 5 is .a perspective view portion thereof cut away to illustrate the reset button; and

as seen along lines of the vent safety switch;

FIG. 6 is a schematic view of the electrical circuitry of this invention.

'The numeral 10 generally designates a gas-fired heating system including a'cabinet 11. A blower 13 is provided in the lower portion of the cabinet 11 and is driven by a motor 15. The numeral 17 generally designates a pluralityof gas burners which are connected to a gas pipe 19. Each of the gas burners 17 extend into an opening 21 in aheat exchanger which is generally designated by the reference numeral 23. The gases created by the combustion of the gas in burners 17 passes upwardly through the chambers 25 of heat exchanger 23 and outwardly through openings 27 as illustrated in FIG. 3. A flue 29 extends from the upper portion of the cabinet 11 and is in communication with the chamber 31 in the cabinet 11 which is in communication with the openings 27. Cabinet 11 is provided with an air vent means 33 formed therein which permits the flow of air into the cabinet 11 from the area surrounding the same. The numeral 35 generally designates a plate which extends downwardly from the upper portion of cabinet 11 in chamber 31 upon which the vent safety switch 37 is operatively mounted.

with portions thereof cut away; 1

of the switch of FlG.4 with a 1 soon becomeapparent to the occupants that the heating system has malfunc- With respect to FlG. 6, the numeral 39 generally designates a source of electricalpower such as 120 volt alternating current and which is connected toa transformer 41 which and operates in conventional fashion. Pilotsafety 49 is connected to the heating system limit control 55 by a lead 57. Limit control 55 includes a temperature sensing element 59 which extends inwardly adjacent the heat exchanger 23. Limit control 55 is connected to a thermostat 61 by a lead 63. Thermostat 61 is connected to oneterminal of the vent safety switch 37 by a lead 65. A second terminal of the switch 37 is connected to the other side of the transformer 41 by a lead 67.

The vent safety switch 37 is normally closed and is temperature sensitive so as to become open at a predetermined temperature. The switch 37 is preferably set to open at 160F. for installation such as illustrated in FIG. 1. The switch 37 is manufactured by the Thermo-O-Disc Company, Mansfield, Ohio and includes a manual reset button 69 which must be operated manually to close the switch once the same has become opened by being subjected to the predetermined temperature which in this case is 160F. The switch 37 includes a temperature sensitive switch disc 71 which protrudes from the upper surface thereof as illustrated in FIG. 4. The reset button 69 can only beoperated upon'the removal of the cover 73 from the switch 37. I 4

In operation, the switch 37 is normally closed and is wired in series'with the gas valve solenoid 43 When the heating system is operating in' proper fashion, the gas valve 47 will remain opento supply gas to the burner 17. The flue gases pass upwardly through the chambers 25, through openings 27, into chamber 31 and upwardly through the flue 29. The air supply for the flue 29 enters the cabinet 11 through the vent 33 and is at room temperature. If the flue 29 becomes blocked, the hot gases build up in the compartment- 31 and expose the switch 37 to the increased temperature. When the temperature adjacent the switch 37 reaches l60, the switch opens thereby breaking the electrical circuit to the solenoid 43 which causes the gas valve 47 to close. The closing of the gas valve 47 obviously causes the burner 17 to be extinguished thereby eliminating further, flue gases from being generated. The fact that the burners 17 are extinguished will I of the building and will indicate to them tioned. The gas valve 47 can only be opened by manually operating the reset button 69 on the switch 37. Thus, the person resetting the switch 37 will beaware that conditions have existed which caused the temperature in the vicinity of the switch to rise to the 160 level. With such knowledge in mind, the person will obviously correct the conditions which existed to cause the switch to be opened.

While the foregoing description has been directed generally to a gas-fired heating system of the forced air type, it should be noted that the switch 37 can be used'for all types of heating systems. The switch 37 may beused on gas heaters where no current is used by simply installing a thermal couple adapter between the thermal couple terminal end and the electro magnet safety power unit.

Thus it can be seen that a unique vent safety switch has been provided which positively closes the gas valve upon the flue becoming plugged. The fact that the switch 37 must be manually reset insures that the person will be advised of the malfunction of the furnace.

Although the vent safety switch 37 has been described as beingmounted in the compartment 31 of the heating system illustrated in .the drawings, it should be noted that the switch may be installed in other locations for other types of heating and the other controls.

systems. For example, the switch could be installed in l vent hoods," vertical draft hoods and conventional draft hoods (compartment 31 Thus it can be seen that the device accomplishes at least all ofits stated objectives I y Some changes may be made in thc'construction and arrangement of our VENT SAFETY SWITCH FOR HEATING SYSTEMS without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims,

any modified forms of structure or use of mechanical equivalents which maybe reasonably included within their scope." g We claim 1. In a heating system: a cabinet; I t a heater means'in said cabinet having a gas-fired burner means connected to asourc'e of gas; a first control 'means operatively connected to said source of gas adaptedio interrupt the flow of gas to said burner means at times;

a flue means in communication with said burner means and extending from said cabinet; said cabinet having an air intake vent means formed therein for permitting'the flow of air into said cabinet fromthe area surrounding the same;

a compartment in said cabinet in between said air intake vent means and said flue means, the temperature in said compartment normally being at approximately the same temperature as the area surrounding said cabinet;

a temperature responsive switch means in said compartment; said switch means being normally closed;

said switch means opening and causing said first control means to interrupt the flow of gas to said burner means when said switch means is subjected to a predetermined temperature in said compartment; and

said switch'means having a manual reset means which is adapted to move, said switch means to its closed position s only when manually operated.

2. The system of clairn'S. wherein said first control means includes a solenoid operated gas valve,said switch means being electrically connected to a sourceof electrical energy and being series connected to said solenoid, said switch means opening when the temperature in said compartment reaches approximately 160F. to cause said solenoid to interrupt the flow of said gas to said burner means. 

